This section provides background information related to the present disclosure which is not necessarily prior art.
Many industrial and automotive components are being made from composite materials in order to reduce weight and reduce material costs as compared to metal components. In addition, the use of composite materials can result in improved molding geometries that result in improved performance such as higher efficiency and quieter operation. Problems exist when using composite materials as rotary working components in a fluid moving device or motor. In particular, composite rotary working components such as impellers, rotors, fan blades, gerotors and other rotary working components of pumps compressors, blowers, fans, and motors can include a metallic insert for fastening purposes. In a particular example, a composite impeller is over-molded on a metallic insert that fastens the impeller to a drive shaft. Failures have occurred due to cracks in the composite material.
The present disclosure provides a metallic insert having smooth contours to provide a mechanical lock in the radial and axial directions so that the composite material of the rotary working component stays in place and the metal insert transmits drive to the composite portion of the rotary working component. The smooth contours of the metallic insert reduce stress concentrations in the composite part when the composite part is mechanically or thermally loaded. The composite part and metallic insert have different coefficients of thermal expansion, which can generate thermal stress on heating/cooling.
Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.